Take back note on pamphlet (7)
I believe the answer is:
retract
'take back' is the definition.
(as in retracting a statement)
'note on pamphlet' is the wordplay.
'note' becomes 're' (as in do-re-mi).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'pamphlet' becomes 'tract' (synonyms).
're'+'tract'='RETRACT'
(Other definitions for retract that I've seen before include "Eat one's words" , "Reverse" , "Withdraw (offer, statement etc)" , "Sheathe" , "Abjure" .)